The present invention relates to a system for controlling the ignition timing of an internal combustion engine, and more particularly to a system for controlling the ignition timing to proper value without occurring the knocking of the engine.
The ignition timing is advanced according to the speed of the engine in order to increase engine power. However, if the ignition timing is largely advanced, knocking of the engine will occur. Therefore, the advance must be controlled so as not to occur the knocking. In order to prevent the knocking, it is necessary to provide sensing means for monitoring operating conditions causing the knocking and to control the ignition timing according to the monitor. Operating conditions causing the knocking can be detected by sensing the vibration of the engine. However, such an indirect detection can not provide an exact control of the ignition timing. Therefore, it is desirable for the exact control to directly detect operating conditions in cylinders.